kernel/trace/trace_mmiotrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Memory mapped I/O tracing
   4  *
   5  * Copyright (C) 2008 Pekka Paalanen <pq@iki.fi>
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/mmiotrace.h>
  10 #include <linux/pci.h>
  11 #include <linux/slab.h>
  12 #include <linux/time.h>
  13
  14 #include <linux/atomic.h>
  15
  16 #include "trace.h"
  17 #include "trace_output.h"
  18
  19 struct header_iter {
  20         struct pci_dev *dev;
  21 };
  22
  23 static struct trace_array *mmio_trace_array;
  24 static bool overrun_detected;
  25 static unsigned long prev_overruns;
  26 static atomic_t dropped_count;
  27
  28 static void mmio_reset_data(struct trace_array *tr)
  29 {
  30         overrun_detected = false;
  31         prev_overruns = 0;
  32
  33         tracing_reset_online_cpus(&tr->array_buffer);
  34 }
  35
  36 static int mmio_trace_init(struct trace_array *tr)
  37 {
  38         pr_debug("in %s\n", __func__);
  39         mmio_trace_array = tr;
  40
  41         mmio_reset_data(tr);
  42         enable_mmiotrace();
  43         return 0;
  44 }
  45
  46 static void mmio_trace_reset(struct trace_array *tr)
  47 {
  48         pr_debug("in %s\n", __func__);
  49
  50         disable_mmiotrace();
  51         mmio_reset_data(tr);
  52         mmio_trace_array = NULL;
  53 }
  54
  55 static void mmio_trace_start(struct trace_array *tr)
  56 {
  57         pr_debug("in %s\n", __func__);
  58         mmio_reset_data(tr);
  59 }
  60
  61 static void mmio_print_pcidev(struct trace_seq *s, const struct pci_dev *dev)
  62 {
  63         int i;
  64         resource_size_t start, end;
  65         const struct pci_driver *drv = pci_dev_driver(dev);
  66
  67         trace_seq_printf(s, "PCIDEV %02x%02x %04x%04x %x",
  68                          dev->bus->number, dev->devfn,
  69                          dev->vendor, dev->device, dev->irq);
  70         for (i = 0; i < 7; i++) {
  71                 start = dev->resource[i].start;
  72                 trace_seq_printf(s, " %llx",
  73                         (unsigned long long)(start |
  74                         (dev->resource[i].flags & PCI_REGION_FLAG_MASK)));
  75         }
  76         for (i = 0; i < 7; i++) {
  77                 start = dev->resource[i].start;
  78                 end = dev->resource[i].end;
  79                 trace_seq_printf(s, " %llx",
  80                         dev->resource[i].start < dev->resource[i].end ?
  81                         (unsigned long long)(end - start) + 1 : 0);
  82         }
  83         if (drv)
  84                 trace_seq_printf(s, " %s\n", drv->name);
  85         else
  86                 trace_seq_puts(s, " \n");
  87 }
  88
  89 static void destroy_header_iter(struct header_iter *hiter)
  90 {
  91         if (!hiter)
  92                 return;
  93         pci_dev_put(hiter->dev);
  94         kfree(hiter);
  95 }
  96
  97 static void mmio_pipe_open(struct trace_iterator *iter)
  98 {
  99         struct header_iter *hiter;
 100         struct trace_seq *s = &iter->seq;
 101
 102         trace_seq_puts(s, "VERSION 20070824\n");
 103
 104         hiter = kzalloc(sizeof(*hiter), GFP_KERNEL);
 105         if (!hiter)
 106                 return;
 107
 108         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, NULL);
 109         iter->private = hiter;
 110 }
 111
 112 /* XXX: This is not called when the pipe is closed! */
 113 static void mmio_close(struct trace_iterator *iter)
 114 {
 115         struct header_iter *hiter = iter->private;
 116         destroy_header_iter(hiter);
 117         iter->private = NULL;
 118 }
 119
 120 static unsigned long count_overruns(struct trace_iterator *iter)
 121 {
 122         unsigned long cnt = atomic_xchg(&dropped_count, 0);
 123         unsigned long over = ring_buffer_overruns(iter->array_buffer->buffer);
 124
 125         if (over > prev_overruns)
 126                 cnt += over - prev_overruns;
 127         prev_overruns = over;
 128         return cnt;
 129 }
 130
 131 static ssize_t mmio_read(struct trace_iterator *iter, struct file *filp,
 132                                 char __user *ubuf, size_t cnt, loff_t *ppos)
 133 {
 134         ssize_t ret;
 135         struct header_iter *hiter = iter->private;
 136         struct trace_seq *s = &iter->seq;
 137         unsigned long n;
 138
 139         n = count_overruns(iter);
 140         if (n) {
 141                 /* XXX: This is later than where events were lost. */
 142                 trace_seq_printf(s, "MARK 0.000000 Lost %lu events.\n", n);
 143                 if (!overrun_detected)
 144                         pr_warn("mmiotrace has lost events\n");
 145                 overrun_detected = true;
 146                 goto print_out;
 147         }
 148
 149         if (!hiter)
 150                 return 0;
 151
 152         mmio_print_pcidev(s, hiter->dev);
 153         hiter->dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, hiter->dev);
 154
 155         if (!hiter->dev) {
 156                 destroy_header_iter(hiter);
 157                 iter->private = NULL;
 158         }
 159
 160 print_out:
 161         ret = trace_seq_to_user(s, ubuf, cnt);
 162         return (ret == -EBUSY) ? 0 : ret;
 163 }
 164
 165 static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 166 {
 167         struct trace_entry *entry = iter->ent;
 168         struct trace_mmiotrace_rw *field;
 169         struct mmiotrace_rw *rw;
 170         struct trace_seq *s     = &iter->seq;
 171         unsigned long long t    = ns2usecs(iter->ts);
 172         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 173         unsigned secs           = (unsigned long)t;
 174
 175         trace_assign_type(field, entry);
 176         rw = &field->rw;
 177
 178         switch (rw->opcode) {
 179         case MMIO_READ:
 180                 trace_seq_printf(s,
 181                         "R %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 182                         rw->width, secs, usec_rem, rw->map_id,
 183                         (unsigned long long)rw->phys,
 184                         rw->value, rw->pc, 0);
 185                 break;
 186         case MMIO_WRITE:
 187                 trace_seq_printf(s,
 188                         "W %d %u.%06lu %d 0x%llx 0x%lx 0x%lx %d\n",
 189                         rw->width, secs, usec_rem, rw->map_id,
 190                         (unsigned long long)rw->phys,
 191                         rw->value, rw->pc, 0);
 192                 break;
 193         case MMIO_UNKNOWN_OP:
 194                 trace_seq_printf(s,
 195                         "UNKNOWN %u.%06lu %d 0x%llx %02lx,%02lx,"
 196                         "%02lx 0x%lx %d\n",
 197                         secs, usec_rem, rw->map_id,
 198                         (unsigned long long)rw->phys,
 199                         (rw->value >> 16) & 0xff, (rw->value >> 8) & 0xff,
 200                         (rw->value >> 0) & 0xff, rw->pc, 0);
 201                 break;
 202         default:
 203                 trace_seq_puts(s, "rw what?\n");
 204                 break;
 205         }
 206
 207         return trace_handle_return(s);
 208 }
 209
 210 static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 211 {
 212         struct trace_entry *entry = iter->ent;
 213         struct trace_mmiotrace_map *field;
 214         struct mmiotrace_map *m;
 215         struct trace_seq *s     = &iter->seq;
 216         unsigned long long t    = ns2usecs(iter->ts);
 217         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 218         unsigned secs           = (unsigned long)t;
 219
 220         trace_assign_type(field, entry);
 221         m = &field->map;
 222
 223         switch (m->opcode) {
 224         case MMIO_PROBE:
 225                 trace_seq_printf(s,
 226                         "MAP %u.%06lu %d 0x%llx 0x%lx 0x%lx 0x%lx %d\n",
 227                         secs, usec_rem, m->map_id,
 228                         (unsigned long long)m->phys, m->virt, m->len,
 229                         0UL, 0);
 230                 break;
 231         case MMIO_UNPROBE:
 232                 trace_seq_printf(s,
 233                         "UNMAP %u.%06lu %d 0x%lx %d\n",
 234                         secs, usec_rem, m->map_id, 0UL, 0);
 235                 break;
 236         default:
 237                 trace_seq_puts(s, "map what?\n");
 238                 break;
 239         }
 240
 241         return trace_handle_return(s);
 242 }
 243
 244 static enum print_line_t mmio_print_mark(struct trace_iterator *iter)
 245 {
 246         struct trace_entry *entry = iter->ent;
 247         struct print_entry *print = (struct print_entry *)entry;
 248         const char *msg         = print->buf;
 249         struct trace_seq *s     = &iter->seq;
 250         unsigned long long t    = ns2usecs(iter->ts);
 251         unsigned long usec_rem  = do_div(t, USEC_PER_SEC);
 252         unsigned secs           = (unsigned long)t;
 253
 254         /* The trailing newline must be in the message. */
 255         trace_seq_printf(s, "MARK %u.%06lu %s", secs, usec_rem, msg);
 256
 257         return trace_handle_return(s);
 258 }
 259
 260 static enum print_line_t mmio_print_line(struct trace_iterator *iter)
 261 {
 262         switch (iter->ent->type) {
 263         case TRACE_MMIO_RW:
 264                 return mmio_print_rw(iter);
 265         case TRACE_MMIO_MAP:
 266                 return mmio_print_map(iter);
 267         case TRACE_PRINT:
 268                 return mmio_print_mark(iter);
 269         default:
 270                 return TRACE_TYPE_HANDLED; /* ignore unknown entries */
 271         }
 272 }
 273
 274 static struct tracer mmio_tracer __read_mostly =
 275 {
 276         .name           = "mmiotrace",
 277         .init           = mmio_trace_init,
 278         .reset          = mmio_trace_reset,
 279         .start          = mmio_trace_start,
 280         .pipe_open      = mmio_pipe_open,
 281         .close          = mmio_close,
 282         .read           = mmio_read,
 283         .print_line     = mmio_print_line,
 284         .noboot         = true,
 285 };
 286
 287 __init static int init_mmio_trace(void)
 288 {
 289         return register_tracer(&mmio_tracer);
 290 }
 291 device_initcall(init_mmio_trace);
 292
 293 static void __trace_mmiotrace_rw(struct trace_array *tr,
 294                                 struct trace_array_cpu *data,
 295                                 struct mmiotrace_rw *rw)
 296 {
 297         struct trace_event_call *call = &event_mmiotrace_rw;
 298         struct trace_buffer *buffer = tr->array_buffer.buffer;
 299         struct ring_buffer_event *event;
 300         struct trace_mmiotrace_rw *entry;
 301         unsigned int trace_ctx;
 302
 303         trace_ctx = tracing_gen_ctx_flags(0);
 304         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_RW,
 305                                           sizeof(*entry), trace_ctx);
 306         if (!event) {
 307                 atomic_inc(&dropped_count);
 308                 return;
 309         }
 310         entry   = ring_buffer_event_data(event);
 311         entry->rw                       = *rw;
 312
 313         if (!call_filter_check_discard(call, entry, buffer, event))
 314                 trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
 315 }
 316
 317 void mmio_trace_rw(struct mmiotrace_rw *rw)
 318 {
 319         struct trace_array *tr = mmio_trace_array;
 320         struct trace_array_cpu *data = per_cpu_ptr(tr->array_buffer.data, smp_processor_id());
 321         __trace_mmiotrace_rw(tr, data, rw);
 322 }
 323
 324 static void __trace_mmiotrace_map(struct trace_array *tr,
 325                                 struct trace_array_cpu *data,
 326                                 struct mmiotrace_map *map)
 327 {
 328         struct trace_event_call *call = &event_mmiotrace_map;
 329         struct trace_buffer *buffer = tr->array_buffer.buffer;
 330         struct ring_buffer_event *event;
 331         struct trace_mmiotrace_map *entry;
 332         unsigned int trace_ctx;
 333
 334         trace_ctx = tracing_gen_ctx_flags(0);
 335         event = trace_buffer_lock_reserve(buffer, TRACE_MMIO_MAP,
 336                                           sizeof(*entry), trace_ctx);
 337         if (!event) {
 338                 atomic_inc(&dropped_count);
 339                 return;
 340         }
 341         entry   = ring_buffer_event_data(event);
 342         entry->map                      = *map;
 343
 344         if (!call_filter_check_discard(call, entry, buffer, event))
 345                 trace_buffer_unlock_commit(tr, buffer, event, trace_ctx);
 346 }
 347
 348 void mmio_trace_mapping(struct mmiotrace_map *map)
 349 {
 350         struct trace_array *tr = mmio_trace_array;
 351         struct trace_array_cpu *data;
 352
 353         preempt_disable();
 354         data = per_cpu_ptr(tr->array_buffer.data, smp_processor_id());
 355         __trace_mmiotrace_map(tr, data, map);
 356         preempt_enable();
 357 }
 358
 359 int mmio_trace_printk(const char *fmt, va_list args)
 360 {
 361         return trace_vprintk(0, fmt, args);
 362 }